John Dick identified the first cancer stem cell, in leukaemia. The widely used xenotransplantation assay that he developed can confirm the identity of prospective haematopoietic stem cells by demonstrating their ability to re-establish a human blood system in the mouse. He is a professor at the University of Toronto and its affiliated Princess Margaret Hospital and Director of the Program in Cancer Stem Cells at the Ontario Institute for Cancer Research.

Chromosome instability is a problem for long-term culture of human embryonic stem cells

Long-term culture of human embryonic stem (hES) cells can cause them to gain or lose large sections of chromosomes, report two papers in Nature Biotechnology. This instability can lessen the reproducibility and reliability of experimental results, and, by raising the specter of cancer, could hinder the clinical application of stem cells.

Checking cell lines in practice is not always easy, experimentally or logistically, says Anselme Perrier of The Institute for Stem Cell Therapy in Evry, France. He and his colleagues discovered that long-term culture of five hES cell lines resulted in a genomic amplification of the 20q.11.21 locus in four cases. "We discovered this mutation during routine quality control" says Perrier, "and it was happening too frequently for it to simply be an artefact".

The ISSCR hopes its handbook will prompt regulators and governments to shut shady clinics

Worried that profit-hungry quacks are exploiting patients and endangering clinical research by offering risky stem cell procedures, the International Society for Stem Cell Research has published documents to warn patients away from fraudulent clinics and to spur government authorities to shut the clinics down.

The society condemned stem cell tourism, saying that shady clinics exploit patients' hopes and could jeopardize "legitimate progress of translational stem cell research."1 Researchers worry clinics promote unreasonable expectations for how quickly mainstream work will progress and generate bad publicity that could tarnish the entire field. Patients and patient advocates often express worry that the scientific community is moving too slowly and say patients should be free to try all options.

Recent studies in cancer treatments point to an ugly truth: the best cells to destroy are the most resistant to attack. Work in several human cancer types indicates that only a subset of cancer cells is capable of regenerating tumours when transplanted into mice. Michael Clarke of Stanford University in Palo Alto, California, one of the first researchers to identify such a subset in a solid tumour1, hypothesized that these cancer stem cells would be less susceptible to chemotherapies than the other cells in the tumour.

New field of epigenetics may hold the secret to flipping cancer's "off" switch. Longtime cancer researcher Jean-Pierre Issa, MD, recalls the evening in May of 1992, when he sat in a San Diego hotel room leafing through the program for the American Association for Cancer Research annual conference. Among the thousands of presentations listed, he spotted only two that mentioned epigenetics. One of them was his.